In recent years a dramatic rise in use of methamphetamine (MA) has prompted a serious research effort to[unreadable] identify the neurobiological substrates that underlie the development of MA addiction. Despite substantial[unreadable] progress, an understanding of the neurochemical systems that mediate the motivational aspects of drugseeking[unreadable] remains incomplete. A key example is our lack of information on the role of acetylcholine (ACh)[unreadable] receptors in MA addiction. A large proportion of MA addicts also self-administer the cholinergic agonist[unreadable] nicotine by smoking but we have only a rudimentary understanding of the role nicotinic receptors might play[unreadable] on the maintenance of MA addiction. To expand this understanding, we need to know how MA-seeking[unreadable] affects the release of ACh and conversely, how manipulations of the cholinergic system affect MA-seeking[unreadable] behaviors. To accomplish the first goal we will use microdialysis to measure ACh in the nucleus accumbens,[unreadable] dorsolateral striatum, hippocampus and prefrontal cortex of B6D2F1 mice that are trained to press a lever to[unreadable] self-administer MA through chronically implanted ICV cannulae. The results from these mice will be[unreadable] compared to matched controls that will receive equal amounts of MA (or vehicle) in a yoked fashion. This[unreadable] project will provide neurochemical data on structures relevant to drug-seeking for use in other components of[unreadable] this research center. The second aim will be to study the induction of transcription factors (ITF's) in[unreadable] cholinergic cells, identified by co-labeling for ChAT, and terminal fields after active and passive MA[unreadable] administration inB6D2Fl mice and in mice selectively bred in Scientific Component 6 for differences in MA[unreadable] drinking and MA-induced locomotor sensitization. In addition to regional changes in molecular signaling[unreadable] events such as ITF levels, we will measure the effect of active and passive MA on the choline uptake and[unreadable] vesicular ACh transporters. Finally, a third set of experiments will study the impact of brain-site specific[unreadable] microinjections of nicotinic and muscarinic drugs on the reinstatement of MA-seeking behavior in response to[unreadable] a stressful stimulus. These studies will address the issue of "stressor responsivity" and the findings will be[unreadable] directly relevant to work being done in the clinical and the behavioral genetic components of the center.